a) Field of the Invention
This invention relates to intermediate bulk containers (also known as "Big Bags") of flexible woven fabric, particularly for use with flowable materials in powder, granular or flake form, such as bulk chemicals, plastics in raw form and the like.
b) Description of the Related Art
Flexible bulk containers are well known, as exemplified by U.S. Pat. No. 4,136,723, or E.P. 0,047,389 A1. It is widely recognised that the walls of flexible bulk containers filled with flowable materials curve outwardly and tend towards a circular shape in horizontal cross section, even though the base may be square. However the storage or transportation of materials in circular bags is very wasteful of space. It has therefore been proposed to make bags with a construction such that they will adopt a square or rectangular shape when filled. One known bag from Haberl of Austria has walls forming a square and bridging panels across each of the corners, these bridging panels being provided with apertures so that powder can flow into the triangular spaces at the corners. However the known bag is made up from a multiplicity of separate panels of fabric, which is disadvantageous both during manufacture and in use.